condition mean min max ZT0-3 3.376088333333333 2.0073499999999997 4.485055 ZT4-7 2.26301 2.26301 2.26301 ZT8-11 3.216535 3.216535 3.216535 ZT12-15 6.6874875 5.99746 7.377515 ZT16-19 6.25028 6.25028 6.25028 ZT20-23 5.791365 5.791365 5.791365